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A new optimized band-pass filter for wavelengths is proposed to increase the optical temporal coherence of thermal light. The choice of parameters for this filter is based on solving an optimization problem for finding the most intensely…

Optics · Physics 2019-05-22 Anatoliy I Fisenko , Vladimir F Lemberg

In many applications data are measured or defined on a spherical manifold; spherical harmonic transforms are then required to access the frequency content of the data. We derive algorithms to perform forward and inverse spin spherical…

Astrophysics · Physics 2011-10-28 J. D. McEwen

Image signals typically are defined on a rectangular two-dimensional grid. However, there exist scenarios where this is not fulfilled and where the image information only is available for a non-regular subset of pixel position. For…

Image and Video Processing · Electrical Eng. & Systems 2022-07-15 Jürgen Seiler , André Kaup

We propose a novel adaptive importance sampling scheme for Bayesian inversion problems where the inference of the variables of interest and the power of the data noise is split. More specifically, we consider a Bayesian analysis for the…

Computation · Statistics 2021-07-27 L. Martino , F. Llorente , E. Curbelo , J. Lopez-Santiago , J. Miguez

We investigate the benefits and challenges of utilizing the frequency information in differential equation identification. Solving differential equations and Fourier analysis are closely related, yet there is limited work in exploring this…

Numerical Analysis · Mathematics 2023-11-29 Mengyi Tang , Hao Liu , Wenjing Liao , Sung Ha Kang

Adaptive subtraction is a key element in predictive multiple-suppression methods. It minimizes misalignments and amplitude differences between modeled and actual multiples, and thus reduces multiple contamination in the dataset after…

This paper presents a new approach for tackling the shift-invariance problem in the discrete Haar domain, without trading off any of its desirable properties, such as compression, separability, orthogonality, and symmetry. The paper…

Computer Vision and Pattern Recognition · Computer Science 2017-05-23 Mais Alnasser , Hassan Foroosh

Phase aberration is an inherent side effect of ultrasound imaging due to the speed of sound inhomogeneity nature of human tissues, resulting in focusing error and reduced image contrast. This work introduces a phase aberration correction…

Signal Processing · Electrical Eng. & Systems 2023-08-29 Wei-Hsiang Shen , Yu-An Lin , Pai-Chi Li , Meng-Lin Li

Time-series analysis is critical for a diversity of applications in science and engineering. By leveraging the strengths of modern gradient descent algorithms, the Fourier transform, multi-resolution analysis, and Bayesian spectral…

Signal Processing · Electrical Eng. & Systems 2021-06-23 Daniel E. Shea , Rajiv Giridharagopal , David S. Ginger , Steven L. Brunton , J. Nathan Kutz

This study puts forward a generalization of the short-time Fourier-based Synchrosqueezing Transform using a new local estimate of instantaneous frequency. Such a technique enables not only to achieve a highly concentrated time-frequency…

Signal Processing · Electrical Eng. & Systems 2020-04-21 Duong-Hung Pham , Sylvain Meignen

Reconstructing continuous signals from a small number of discrete samples is a fundamental problem across science and engineering. In practice, we are often interested in signals with 'simple' Fourier structure, such as bandlimited,…

Data Structures and Algorithms · Computer Science 2018-12-24 Haim Avron , Michael Kapralov , Cameron Musco , Christopher Musco , Ameya Velingker , Amir Zandieh

Understanding wireless channels is crucial for the design of wireless systems. For mobile communication, sounders and antenna arrays with short measurement times are required to simultaneously capture the dynamic and spatial channel…

Signal Processing · Electrical Eng. & Systems 2025-09-26 Juan Sanchez , Xuesong Cai , Ali Al-Ameri , Fredrik Tufvesson

Fourier transform methods are used to analyze functions and data sets to provide frequencies, amplitudes, and phases of underlying oscillatory components. Fast Fourier transform (FFT) methods offer speed advantages over evaluation of…

Data Analysis, Statistics and Probability · Physics 2015-07-08 Elya Courtney , Michael Courtney

This note shows how to align a periodic signal with its the Fourier transform by means of frequency or time scaling. This may be useful in developing new algorithms, e.g. for pitch estimation. This note also convolves the signals and the…

Signal Processing · Electrical Eng. & Systems 2023-09-19 Matthew R. Flax , W. Harvey Holmes

The nonlinear Fourier transform has the potential to overcome limits on performance and achievable data rates which arise in modern optical fiber communication systems when nonlinear interference is treated as noise. The periodic nonlinear…

Signal Processing · Electrical Eng. & Systems 2020-12-24 Jan-Willem Goossens , Hartmut Hafermann , Yves Jaouën

This article presents a two-stage topological algorithm for recovering an estimate of a quasiperiodic function from a set of noisy measurements. The first stage of the algorithm is a topological phase estimator, which detects the…

Computer Vision and Pattern Recognition · Computer Science 2016-12-21 Michael Robinson

A simple procedure for the design of recursive digital filters with an infinite impulse response (IIR) and non-recursive digital filters with a finite impulse response (FIR) is described. The fixed-lag smoothing filters are designed to…

Signal Processing · Electrical Eng. & Systems 2025-07-22 Hugh Lachlan Kennedy

The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of temporal and spatial scales. When an interferometer is not sufficiently calibrated for the direction-dependent ionospheric effects, the time-varying…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 S. A. Brackenhoff , M. Mevius , L. V. E. Koopmans , A. Offringa , E. Ceccotti , J. K. Chege , B. K. Gehlot , S. Ghosh , C. Höfer , F. G. Mertens , S. Munshi , S. Zaroubi

The short-time Fourier transform (STFT) usually computes the same number of frequency components as the frame length while overlapping adjacent time frames by more than half. As a result, the number of components of a spectrogram matrix…

Signal Processing · Electrical Eng. & Systems 2020-10-29 Daichi Kitahara

Frequency control reserves are an essential ancillary service in any electric power system, guaranteeing that generation and demand of active power are balanced at all times. Traditionally, conventional power plants are used for frequency…

Systems and Control · Computer Science 2013-12-24 Theodor Borsche , Andreas Ulbig , Göran Andersson